Electromagnetic pulse valve for bag filter

Cleaning is an important measure to ensure the normal operation of the bag filter. If the blowing performance and volume of the pulse valve can not effectively remove the dust cake formed on the dusty surface of the filter bag, the resistance of the dust collector (inlet and outlet pressure difference) will be caused. Ascending, the negative pressure of the dust source collection port decreases, and the treatment air volume decreases, which in turn deteriorates the operating conditions of the entire system. Once the resistance cannot be controlled and continues to rise, the precipitator will be in a paralyzed state. Conversely, excessive dusting will cause the dust collector to have too low resistance, which will increase the discharge of particulate matter (especially fine particulate matter), and affect the filter bag. Since the pulse valve's blowing performance and gas volume are important for the cleaning effect of the bag filter, It is also subject to various factors in the cleaning system, and it is difficult for the pulse valve manufacturer to answer how many filter bags (filtration area) a pulse valve can clean. Although some pulse valve manufacturers also have a blow test device, due to the lack of test-specific dust and special cleaning test devices, at best, only the amount of gas injected by the pulse valve under limited conditions and the pressure at each point of the filter bag during injection can be measured. distributed. Some large-scale dust collector backbone enterprises in China have a bag filter test bench, which can determine the material, diameter, length and combination number of the filter bag. It can be used in different dust concentration, discharge concentration, filtration speed, pulse valve of different caliber and requirements. Under the conditions of equipment resistance and emission requirements, the test determines the cleaning ability of the pulse valve, which provides a scientific basis for the selection of the pulse valve and the design of the cleaning system.

The baghouse dust cleaning device is a system. The pulse valve releases the cleaned air source, which also needs to be transported through the blow tube and distributed to each filter bag. The airflow from the nozzle (nozzle) on the spray pipe causes the pressure in the filter bag to rise rapidly and shakes the filter bag, so that the dust cake gathered on the dust-collecting surface of the filter bag can be peeled off, and the best combination of various factors can be obtained to obtain the best. effect.

After determining the parameters of the precipitator, the designer of the bag filter determines the required pulse valve according to the cleaning requirements. The author wants to give an example to illustrate: the manufacturer of the drug indicates the method and dosage of the drug in the product manual, but most patients still take the drug according to the doctor's decision. Although the drug is the same, the situation of each patient is They are different, so the amount of medication is also different. The responsibility of the drug factory is to ensure the quality of the drug, and the doctor's duty is to guide the patient to use the drug correctly. The “doctor” in the selection of the pulse valve is the designer of the bag filter.

2. The electromagnetic pulse valve injection volume is restricted by many factors.

How many filter bags (filter area) can be sprayed by an electromagnetic pulse valve? A row of filter bags knows the diameter, length and number of filter bags of the filter bag. It needs to be equipped with a few inch pulse valve. This kind of problem is often encountered, especially just engaged. The person who designed the bag filter is the answer he needs first. Indeed, the electromagnetic pulse valve is a key component of the pulse jet bag filter cleaning system. A dust collector can only maintain its set resistance and ensure the normal operation of the device if it has a reliable and effective cleaning function. But so far there is no way and method to quickly determine the answer to the above questions, and there is no formula for calculation.

The amount of gas injected by the electromagnetic pulse valve is the key to determining how many filter bags (filtration area) can be cleaned, but it is not scientific to determine the cleaning capacity of the electromagnetic pulse valve only. Because some pulse valves can not be closed in time, the amount of air injected is not only affected by the consumption of compressed gas, waste of energy, but also no effect on filter bag cleaning. For pulse valves with good performance and quality, the volume of the blown air is also subject to many factors in the cleaning system: from the input end of the pulse valve, the volume and pressure of the gas distribution box, the gas distribution box The inner diameter of the gas pipe and the gas supply capacity of the gas source directly affect the blowing performance and the blowing gas volume of the same pulse valve: at the load end of the electromagnetic pulse valve, that is, the filter bag it blows, the temperature of the dust-containing gas is filtered, Humidity, dust concentration, specific gravity and viscosity, filtration speed and equipment resistance all have different requirements on the blowing performance and gas volume. The number and structure of the nozzle (nozzle) of the blowing pipe, the material of the filter bag, the diameter, the length and the quantity, and the cleaning Various factors such as form (online, offline), cleaning control (timing, constant pressure difference), etc., affect and restrict the blowing performance and cleaning effect of the pulse valve to varying degrees.

3. Responsibilities of electromagnetic pulse valve manufacturers

Electromagnetic pulse valve manufacturers should actively cooperate with users to provide various data including pulse valve including air volume, as well as test methods and test equipment for this data, to provide successful cases in applications, and to provide some suggestions based on their own experience. And to track the actual use of new users, new conditions to complement and enrich themselves, improve the ability and level of service to users.

The various data and information provided by the electromagnetic pulse valve manufacturer to the user should be true and responsible. Some companies have indicated in their product introduction that the pulse valve can spray the area of the filter bag. If there is a basis, it is a good thing. But take a closer look: the right angle valve, submerged valve, straight-through valve and other different types of pulse valve listed in the same specification are the same value. Different forms of pulse valve structure, gas source pressure, blowing performance and gas volume are different, and the blowing area cannot be the same. This is harmful to yourself, to users, and to the development of the industry.

4. Bag dust removal is a "science plus art" industry

A foreign scholar once described the bag dust removal technology as "science plus art." The author's understanding is to master and apply this technology, not only to understand and be familiar with its scientific principles, but also to continue to accumulate valuable experience in practice. Today it can be said that China has applied the dust bag big country, and there were many leading experts in the iron and steel, nonferrous metals, building materials, electricity, chemicals, waste incineration and other industries, in Cheongju baghouse ash optional pulse valve system aspects Create unique experiences and methods. Through successful project cases, they judged whether the pulse valve blowing capability is rich or not, and then increase or decrease the cleaning area in future projects. They determined through experiments that the amount of spray required to clean the filter bag per square meter was between a few liters. Some scholars have their own unique methods for estimating the gas volume through analysis of many projects. Of course these are all empirical data. To use empirical data, you must first have experience, and you have a certain amount of experience in order to use these empirical data correctly. It is believed that with the development of the bag dust removal industry and the improvement of the cleaning technology, the correct method of matching the pulse valve will be mastered by more people.